Fair Value Disclosures - Schedule of Undiscounted Amount of Contingent Consideration (Detail) - Jun. 30, 2015 - CureTech Ltd [Member] - USD ($) $ in Thousands	Total
Business Acquisition, Contingent Consideration [Line Items]
Potential payment upon completion of Manufacturing Technology Transfer	$ 5,000
Minimum [Member]
Business Acquisition, Contingent Consideration [Line Items]
Potential future tiered royalties on annual worldwide net sales	5.00%
Maximum [Member]
Business Acquisition, Contingent Consideration [Line Items]
Potential future tiered royalties on annual worldwide net sales	11.00%
Sales milestones earned [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business acquisition maximum contingent consideration	$ 245,000
Development milestones earned [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business acquisition maximum contingent consideration	$ 85,000

Dollar amount of future milestone payment for Technology transfer under manufacturing services agreement.

No definition available.

Name:	mdvn_FutureMilestonePaymentForTechnologyTransferUnderManufacturingServicesAgreement
Namespace Prefix:	mdvn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Range of percentage rates for royalties paid annual worldwide net sales, as defined by license agreement.

+ References

No definition available.

+ Details

Name:	mdvn_RoyaltiesPaidAtPercentageRateRanging
Namespace Prefix:	mdvn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionContingentConsiderationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)(3)

-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_BusinessAcquisitionAxis=mdvn_CureTechLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=mdvn_SalesMilestonesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=mdvn_DevelopmentMilestonesEarnedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: